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42 lines
881 B
Rust
42 lines
881 B
Rust
fn factorial(num: u64) -> u64 {
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// TODO: Complete this function to return the factorial of `num` which is
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// defined as `1 * 2 * 3 * … * num`.
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// https://en.wikipedia.org/wiki/Factorial
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//
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// Do not use:
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// - early returns (using the `return` keyword explicitly)
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// Try not to use:
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// - imperative style loops (for/while)
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// - additional variables
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// For an extra challenge, don't use:
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// - recursion
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}
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fn main() {
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// You can optionally experiment here.
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn factorial_of_0() {
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assert_eq!(factorial(0), 1);
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}
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#[test]
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fn factorial_of_1() {
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assert_eq!(factorial(1), 1);
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}
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#[test]
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fn factorial_of_2() {
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assert_eq!(factorial(2), 2);
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}
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#[test]
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fn factorial_of_4() {
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assert_eq!(factorial(4), 24);
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}
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}
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